Outside of Inglewood and New Plymouth - New Zealand me and 4 other people spotted 5 circular disc shaped objects in the sky.

I was headed down state highway 3 from palmerston north to new plymouth in my car. We had the radio tuned to 94 fm: the edge. We were headed into New Plymouth at the time and i knew there was enough coverage in the area to keep the radio waves going. The radio started giving a static buzz at about the time we left inglewood.This continued for about 1 minute and we decided to switch the radio off. As we approached the next corner I saw an orange light over the trees. It soon vanished. As we neared the sighting spot we slowed down to see what it may have been. Nothing unusual could be seen. We retained speed through the next few corners and something orange hovered above us. It appeared to be about 100 feet from the ground and looked to be between 30 and 50 feet long and the same in width (basically circular). There were five of us in the car at the time:Me, my brother, his girlfriend, their friend and a friend of my own. We all could see it. The object seemed to hover soundlessly as we all stepped out of the car. As we looked around we saw three other objects hovering and swaying around in the air. They looked like they were changing colour from metallic glowing orange to metallic deep purple and shades of blue. One more larger object appeared on the horizon and sped towards the other 4. Each seemed to react in a way similiar to an army unit and formed a line and dissapeared almost instantly over towards Mount Taranaki. As we left several minutes later we realized we hadn't seen any traffic for about half an hour and only saw some as we entered new plymouth.